Posterior tibialis tendon pain and dysfunction is a problem whose early diagnosis and treatment may prevent significant disability and surgery. Pain in the region of the medial maleolus and arch is sometimes difficult to attribute to a specific anatomical structure based on clinical exam, especially early in the course of posterior tibial tendon dysfunction. Therefore, many patients with posterior tibial tendon dysfunc-tion may go undiagnosed. Magnetic resonance imaging (MRI) is the current standard diagnostic imaging technique utilized in the diagnosis of foot and ankle problems. Our study is designed to determine if there is a correlation between the clinical exam, ultra- sonography, and MRI, and determine if MRI can be replaced with the less expensive and readily available ultrasound examination. This study began enrolling volunteers in November 1997. We have studied 15 normal volunteers and 26 individuals with foot pain so far. No complications were encountered. We plan to continue the protocol to enroll 30 patients with foot pain as projected. We were able to visualize the posterior tibialis tendon and the flexor digitorum longus tendons well by both magnetic resonance imaging (MRI) and sonography. Statistical measurements are being made to determine the range of normal measurements of the tendons and to determine whether there is good correlation between findings seen on MRI, sonography, and clinical evaluation. Preliminary findings were presented at the annual meeting of the American Roentgen Ray Society in May. We hope to publish our data soon.